Polyvinyl acetal acid dicarboxylates and their preparation



United States Patent 25828.289" POLYVINYL ACETAL ACID DIGARBOXYLATES:

AND THEIR PREPARATION I JohnW i Mencli, Rochester, Ni Y assignonto"Eastman Kodak Company, Rochester, N. Y'.,. a" corporation of New JerseyNb Drawing Applicationlyl archfllflfi V senalNo. 493,289

9"Cla'im's c1; Mil -73) This invention relates to the preparation ofpolyvinyl acetal acid dicarli'oxylates' in which polyvinyl alcohol is"ice malbutyraldehyde benzaldehyde and the like. The polyvinylalcoholior polyvinyl acetate is converted to, the acetal form byreacting upon 1 part thereof with the aldehyde in the presence of.001.05 part of mineral acid catalyst 5 preferably with a. diluentparticularly a lower fatty acid converted to polyvinyl acetal andthismaterial is then est'e'ritie'd witha dicarhoxylic acid anhydride.

At thepresent time thereis considerable interest in water solublecompounds of a polymeric naturehaving better solubili ties cold thanhot, thus resembling gelatin. 'In the u'seof comp ounds of this type incoating; operations the coating" solutionmay be applied" at ordinarytemperatures and then by the use of heat; setting or increasing of theviscosity of'the coating is obtained.

One object of my invention is to prepare compounds the salts of whicharewatersoluble cold but at elevated temperatures the solubility thereofis decreased. Another} 'ohje'ct of my invention is to provide a processfor -making pol'yvin r acetal-dic'arboxylates in which polyvinylalcoholis c n'verted to theacetal and then esterified without firstisolating thematerial. Other objects of my inventio'ii will appearherein. 7 7

In itsbroadest aspects my invention comprises reacting upon polyvinylalcohol or at hydrolyzed polyvinyl acetate withan-aldehyde and a mineralacid catalystto form polyvinyl acetal and converting the mass toesterification: conditions to obtain apolyvinyl'.acetalldicarboxylate.My in- I vention has'for its purpose thepreparation of end products asreferred to' herein with-the? elimination of two major disadvantages:(1) the necessity of isolation of the. intermediate acetal and .(2) theelimination of the pyridine catalyst in the esterification step. I e Ihave found/that the condensation of polyvinyl alcohol or hydrolyzedpolyvinyl acetate with an aldehyde is advantageously carried out in thepresence of acetic acid asthe solvent using only an extremely smallamount of a mineral acid such as hydrochloric or sulfuric acid as 'thecatalyst. A-t elevated temperatures the acetalation reaction isextremely rapid, the extent thereof being governed by the amount ofaldehyde employed. After the reaction is completed the mass may beconverted, without cooling to esterification conditions by addingthereto an alkali metal acetate such as sodium, potassium or lithium--acetate in suflicient quantity to neutralize the-mineral acid catalysttherein and to supply a suificient additional amount thereofto catalyzethe esterification of thepolyvinyl acetal with a dibasic acid anhydridesuch as phthalic anhydride. The extent of the esterification iscontrolled by the amounts of the catalyst and the dicarboxylic anhydrideemployed. 7

The preparation of the polyvinyl acetal is carried out by reacting uponpolyvinyl alcohol or hydrolyzed polyvinyl acetate with an aldehyde.Ordinarily thecompound known as polyvinyl alcohol retains less than 5%of polyvinyl acetate upon its preparation by hydrolyzing polyvinylacetate. My invention may use as the starting material polyvinyl acetatewhich has been hydrolyzed to an extent of 50-100%. Any of the ordinaryaldehydes may be employed to carry on the acetalation reaction. Somealdehydes which have been found to be particularly useful areacetaldehyde, paraldehyde isobutyraldehyde, norsuch asjacetic' acidbeingpresent. This reaction occurred in a short time; upon'heating such as bymeans of a steam bath. After the acetal formation there was thena'd'ded'to' the mass sodium acetate in an amount suflicient tocompletely neutralize the mineral acid catalyst plus *an'fadditionofmore sodium acetate or otherv alkali metal acetate to constitute.5.5.00 of, polyvinyl compound which. is. present,..the amount. usedbeing that which will most satisfactorily promote thex reaction of thedicarboxylic acid anhydride upon the polyvinyl acetal. A1130 added isdicarboxyliaacid anhydride inv an. amount which will supply phthalyl orother dicarboxylic acid groups: to essentially: allr of the hydroxylgroups of the polyvinyl acetalwhich 'is being reacted. upon. Thereaction i's -ca'rri'e'd out at am elevatedtemperature such as of 1'51)?F, the temperature employed; being only limited by: the boilingtemperatures of the materials employed in the: reaction mass temperatureof 160-200? F. is: very convenient formost reactions: in accordance withmy inventi'on'; although my invention is not limited to that range.After the reaction has occurred the mass. is preferably cooled and. theproduct obtained may be conveniently separated from the mass by addingwater there- Example 1' One part of. commercial polyvinyl alcohol wasmixed with 1;09 parts of isobutyra1dehyde,,9.1 parts of acetic acid and0.0036 partof concentrated hydrochloric'acid for /2' hour atapproximately C. A clear dope was obtained. There was then added /2 partof anhydrous f sodium acetate followedby the addition of 1.82 parts oftetrahydrophthalic anhydride. The stirring was continued for 3 /2. hoursat about 95 C tThe reaction mixture obtained was diluted with acetoneand precipitated into esterified water. The material obtained was washedand dried withdistilled water and the product was analyzed with thefollowingresults:

Percent polyvinyl tetrahydrophthalate 25.2 Percent polyvinyl alcohol14.9 Percent polyvinyl isobutyral 59.9

Example 2 One part of polyvinyl alcohol was mixed'with 0.68 part ofbenzaldehyde,9.1 parts of acetic acid and 0.0036 part ofconcentrate-dhydrochloric acid for 1% hours at about 95 C. A clearsolution was obtained. There was added to this mass /2 part of anhydroussodium acetate and 2.27 parts of .succinic anhydride and the stirringwas continued for 3% hours at .about 95 C. A gel resulted which upondilution With acetone-Water formed a clear solution. The product wasisolated as described in the' preceding example. Upon analyses thefollowing results were obtained:

Percent polyvinyl succinate 49.4 Percent .polyvinyl alcohol 18.2 Percentpolyvinyl benzal 32.4

3.. Example 3 7 One part of polyvinyl alcohol was mixed with 1.09 partsof n-butyraldehyde, 0.0036 part of concentrated hydro? chloric acid and9.1 parts of acetic acid for 20minutes at about 95 C. A clear dope wasobtained. There was then added /2 part of anhydrous sodium acetate and2.27 parts of diglycolic anhydride and the mixing was continued for 1hour at about 95 C. The mass formed a gel which when diluted withacetone-water gave a clear solution. The product obtained was isolatedas described in the preceding examples. Analyses of the product gave thefollowing results:

Percent polyvinyl diglycolate 20.6

Percent polyvinyl alcohol 11.9

Percent polyvinyl butyral 67.5

Example 4 Percent polyvinyl 3-nitrophthalate 55.2 Percent polyvinylalcohol 16.5 Percent polyvinyl bemal 28.3

Example 5 Polyvinyl alcohol was reacted with aldehyde and thenWith'phthalic anhydride in several batches, the proportions employedbeing indicated in the following table.

In all cases the polyvinyl alcohol reacted sufficiently rapidly with thealdehyde that solution occurred within 10 minutes. Theesterificationstep was of about 2-4 hours duration at steam bathtemperatures. The product was isolated by precipitation into esterifiedwater. All the samples were soluble in dilute aqueous alkali or ammoniaalthough in the case of the low phthalyl'products cooling was desirable:

Parts of A B C D E F Polyvinyl Alcohol 15 15 15 15 15 15 Acetic acid 150150 150 150 150 150 Gone. HCl, ml. 0.05 0. 05 0.05 0.015 0.05 0.015Paraldehyde 3 5 7. 6 7. 5 7. 5 11. 25 Sodium acetate- 6 5 5 5 5 5Phthalic anhydride 15 15 15 15 45 15 Analysis:

Percent Phthalyl 18. 1 11.8 6. 5 5.7 19. l 3. 8 Percent P. V. Alcohol23. 7 15. 6 14. 1 16.4 4.1 9.3

The products which were obtained by the procedures described in theexamples were in the acid form but could readily be converted to watersoluble salts thereof by reacting with dilute aqueous solutions ofalkalies, am monia or aliphatic amines. The water-soluble compounds thusformed exhibit less solubility or higher viscosity in water at elevatedtemperatures than when cool or at room temperatures. These products areuseful for coating purposes or as protective colloids. For instance,products of this type may be employed as the protective colloid forsilver halides in photographic emulsions. In this use it may sometimesbe desirable to employ mixtures of aldehydes in preparing the acetals inwhich some of the aldehyde employed may contain groups which arereactive for various purposes in the intended use. For instance, inphotographic emulsion it might be desirable to employ some aldehydeshaving coupler groups such as those having an aromatic nucleuscontaining phenolic OH, ialkoxy, aryloxy, amino, alkylamino, orarylamino and having a.

reactive position ortho or para to those groups or those having anactive methylene group, so as to make polyvinyl acetal dicarboxylates inaccordance with the process of our invention useful in colorphotography. The compounds in accordance with our invention may also beemployed for removable layers in that they may be insoluble in acidsolutions but upon treatment with alkaline solutions are readilyremovable from the surface upon which they have been applied such asbacking layers or the like or for enteric purposes.

I claim: 7

1. A method of making polyvinyl acetal dicarboxylates which comprisesreacting upon polyvinyl acetate, which has been 50-100% hydrolyzed, withan aldehyde in the presence of .001-.5 part of mineral acid catalyst perpart of polyvinyl compound, adding to the mass without precipitating theproduct therefrom an alkali metal acetate in suflicient amount toneutralize the mineral acid and to provide an excess of the alkali metalacetate in an amount 5'500% of the polyvinyl compound present togetherwith a dicarboxylic acid anhydride and reacting the mass until 'asubstantial dicarboxyl content is imparted to the polyvinyl compoundtherein.

2. A method of preparing polyvinyl acetal dicarboxylate s whichcomprises reacting polyvinyl alcohol with an aldehyde in the presence of.00l-.05 part of mineral acid catalyst per part of polyvinyl alcohol,and without precipitating the product therefrom, adding sodium acetateto the mass in suflicient amount to neutralize the mineral acid catalystand toprovide 5-500% thereof based on the polyvinyl alcohol plusdicarboxylic acid adding to the mass suflicient alkali metal acetate toneutralize the mineral acid catalyst and to provide 5500% of alkalimetal acetate based on the polyvinyl compound present plus phthalicanhydride and reacting upon the "polyvinyl compound until a substantialphthalyl content is imparted thereto.

4. A method of preparing polyvinyl acetal phthalates which comprisesreacting upon polyvinyl acetate, 50-

100% hydrolyzed, with an aldehyde and a mineral acid catalyst, andwithout precipitating the product therefrom, adding to the mass sodiumacetate in sulficient amount to neutralize the mineral acid catalyst andto constitute 5-500% based on the polyvinyl compound present plusphthalic anhydride and reacting the phthalic "anhydride with thepolyvinyl compound present until a substantialphthalyl content isimparted thereto.

5. A method of preparing polyvinyl acetal dicarboxylates which comprisesreacting polyvinyl alcohol "with paraldehyde and a mineral acidcatalyst, and without precipitating the product therefrom, adding to themass sodiumacetate in sufiicient amount to neutralize the mineral acidplus phthalic anhydride and reacting 'upon the polyvinyl compoundpresent with the phthalic anhydride until a substantial phthalyl contentis imparted thereto.

6. A method of preparing polyvinyl acetal dicarboxylates which comprisesreacting upon polyvinyl aljcohol with benzaldehyde and a mineral acidcatalyst,

and without precipitating the product therefrom, adding to the masssodium acetate in sufiicient amount to neutralize, the mineral acid andto provide 5500% thereof based on the polyvinyl compound present plusnitrophthalic anhydride and reacting upon the polyvinyl compoundpresent'with the nitrophthalic anhydride to impart a. substantialnitrophthalyl content to the polyvinyl compound.

7. A 'method of preparing polyvinyl acetal diglyco- 5 late whichcomprises reacting upon polyvinyl alcohol with butyraldehyde and amineral acid catalyst, and without precipitating the product therefrom,adding to the mass an amount of sodium acetate in excess of that.

necessary to neutralize the mineral acid present plus diglycolicanhydride and reacting upon the polyvinyl compound with the diglycolicanhydride so as to impart a substantial diglycolyl content to thepolyvinyl compound present.

8. A method of preparing a polyvinyl acetal succinate which comprisesreacting polyvinyl alcohol with benzaldehyde and a mineral acidcatalyst, and without precipitating the product therefrom, adding to themass sodium acetate in excess of that necessary to neutralize themineral acid present plus succinic anhydride and reacting upon thepolyvinyl compound with the succinic anhydride for a sufiicient time toimpart a substantial succinyl content thereto.

9. A method of preparing a polyvinyl acetal tetrahydrophthalate whichcomprises reacting upon polyvinyl alcohol with isobutyraldehyde and amineral acid cata- References Cited in the file of this patent UNITEDSTATES PATENTS 2,129,450 Talbot June 17, 1936 2,169,250 Izard May 27,1937 2,333,796 Kenyon et a1. June 13, 1940 2,380,032 Dorough Mar. 24,1942 2,413,275 Wilson et al. Aug. 27, 1943 2,484,415 Malm et a1. Aug.10, 1945 OTHER REFERENCES Kainer: Polyvinylalkahole, published by Enke,Stuttgart, Germany (1949), pages 56-61. (Copy in Scientific Library.)

1. A METHOD OF MAKING POLYVINYL ACETAL DICARBOXYLATES WHICH COMPRISESREACTING UPON POLYVINYL ACETATE, WHICH HAS BEEN 50-100% HYDROLYZED, WITHAN ALDEHYDE IN THE PRESENCE OF .001-5 PART OF MINERAL ACID CATALYST PERPART OF POLYVINYL COMPOUND, ADDING TO THE MASS WITHOUT PRECIPITATING THEPRODUCT THEREFROM AN ALKALI METAL ACETATE IN SUFFICIENT AMOUNT TONEUTRALIZE THE MINERAL ACID AND TO PROVIDE AN EXCESS OF THE ALKALI METALACETATE IN AN AMOUNT 5-500% OF THE POLYVINYL COMPOUND PRESENT TOGETHERWITH A DICARBOXYLIC ACID ANHYDRIDE AND REACTING THE MASS UNTIL ASUBSTANTIAL DICARBOXYL CONTENT IS IMPARTED TO THE POLYVINYL COMPONDTHEREIN.